Various pneumatic staple guns have been developed for driving staples into wood, etc. The magazine of a regular pneumatic staple gun, as shown in FIG. 1, is generally comprised of a magazine cover 10' and a magazine base 20'. The magazine cover 10' has a front end fixedly mounted with a stop plate 11' and a rear end fixedly mounted with an end plate 12'. The end plate 12' projects over the rear end of the magazine base 20', having a finger strip 121' at right angles. A follow plate 13' is connected to the magazine cover 10' by a spring 131' and moved in a longitudinal groove 101' on the magazine cover 10' to force staples into position for driving. A mounting plate 21' is fixedly secured to the top side of the magazine base 20' near the rear end to hold a spring plate 22' and a projecting plate 23'. By means of the mounting plate 21', the magazine base 20' is fastened to the gun body 30'. When assembled as shown in FIG. 2, the spring plate 22' is stopped at the end plate 12', causing the magazine cover 10' and the magazine base 20' firmly retained together. When to open the magazine base 20' for loading staples, the spring plate 22' is lifted from the end plate 12' as shown in FIGS. 3 and 4, then the finger strip 121' is pulled backwards by hand, causing the magazine cover 10' moved backwards relative to the magazine base 20'. When the magazine cover 10' is moved backwards relative to the magazine base 20', the stop plate 11' will be stopped by the projecting plate 23' to limit the backward movement of the magazine cover 10' relative to the magazine base 20'. When staples are loaded, the magazine cover 10' is moved forwards to its former position, permitting the spring plate 22' to stop at the end plate 12' again. This structure of magazine is still not satisfactory in function. Drawbacks of this structure of magazine is outlined hereinafter.
1) Because the magazine cover 10' and the magazine base 20' are firmly retained together by stopping the spring plate 22' at the end plate 12', when to pull the magazine cover 10' backwards from the magazine base 20', the operator shall have to lift the spring plate 22' with the forefinger and stop the finger strip 121' with the thumb. When the spring plate 22' is separated from the end plate 12', the spring plate 22' must be supported by the forefinger for permitting the magazine cover 10' to be pulled backwards by the thumb. It procedure is complicated. PA0 2) Because the stop plate 11', the finger strip 121', the projecting plate 23', and the spring plate 22' protrude over the magazine base 20', they tend to injure the user's hands during the operation of the pneumatic staple gun. Furthermore, these protruding elements destroy the sense of beauty of the pneumatic staple gun. PA0 3) Because the end plate 12' is made from a metal sheet by a punching machine, the hand tends to be injured by the end plate 12' when moving it. PA0 4) The rear end of the magazine base 20' tends to deform quickly with use, causing the magazine cover 10' unable to be closely covered on the magazine base 20'.